The present invention relates to a power transmission chain, and more particularly, to a power transmission chain, a method of manufacturing the power transmission chain, and a power transmission apparatus suitable for a continuously variable transmission (CVT) for vehicles.
A continuously variable transmission for vehicles known in the art, as shown in FIG. 7, includes a driving pulley 2 having a stationary sheave 2a and a movable sheave 2b and connected to an engine, a driven pulley 3 having a stationary sheave 3b and a movable sheave 3a and connected to driving wheels, and an endless power transmission chain 1 wound around the pulleys. As for the continuously variable transmission, the chain is clamped by hydraulic force by moving the movable sheaves 2b and 3a to or away from the stationary sheaves 2a and 3b using a hydraulic actuator, contact load between the pulleys 2 and 3 and the chain 1 is generated from the clamping force, and torque is transmitted by frictional force at the contact portions therebetween.
Disclosed in JP-A-8-312725, a power transmission chain includes a plurality of links having front and rear inserting portions into which pins are inserted, a plurality of first pins and second pins connecting links that are arranged in a width direction of the chain such that the front inserting portion of a link corresponds to the rear inserting portion of another link, and enabling them to longitudinally bend with respect to each other. As for the above power transmission chain, a first pin fixed to the front inserting portion of a link and movably inserted in the rear inserting portion of another link and a second pin movably inserted in the front inserting portion of the former link and fixed to the rear inserting portion of the later link relatively move through rolling-contact, and the links longitudinally bend.
It is required for improving durability for the above power transmission chain, because the durability of links is particularly important. Further, it is also important to reduce noise. However, because the shape of the front and rear inserting portions of links determined in designing are slightly deformed in a manufacturing process, a desired effect of reducing noise cannot be obtained in a complete chain.